[Distutils] Working toward Linux wheel support

[Chris Barker]

On Tue, Jul 21, 2015 at 9:38 AM, Oscar Benjamin <oscar.j.benjamin at gmail.com>
wrote:

>
> I think it would be great to just package these up as wheels and put them
> on PyPI.
>

that's the point -- there is no way with the current spec to specify a
wheel dependency as opposed to a package dependency. i.e this particular
binary numpy wheel depends on this other wheel, whereas the numpy source
pacakge does not have that dependency -- and, indeed, a wheel for one
platform may have different dependencies that\n other platforms.



> So numpy could depend on "blas" and there could be a few different
> distributions on PyPI that provide "blas" representing the different
> underlying libraries. If I want to install numpy with a particular one I
> can just do:
>
>     pip install gotoblas  # Installs the BLAS library within Python dirs
>     pip install numpy
>

well,different implementations of BLAS are theoretically ABI compatible,
but as I understand it, it's not actually that simple, so this is
particularly challenging.

But if it were, this would be a particular trick, because then that numpy
wheel would depend on _some_ BLAS wheel, but there may be more than one
option -- how would you express that????

-Chris






> You could have a BLAS distribution that is just a shim for a system BLAS
> that was installed some other way.
>
>     pip install --install-option='--blaslib=/usr/lib/libblas' systemblas
>     pip install numpy
>
> That would give linux distros a way to provide the BLAS library that
> python/pip understands without everything being statically linked and
> without pip needing to understand the distro package manager. Also python
> packages that want BLAS can use the Python import system to locate the BLAS
> library making it particularly simple for them and allowing distros to move
> things around as desired.
>
> I would like it if this were possible even without wheels. I'd be happy
> just that the commands to download a BLAS library, compile it, install it
> non-globally, and configure numpy to use it would be that simple. If it
> worked with wheels then that'd be a massive win.
>
> --
> Oscar
>



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